Electrostatic actuation is one of the most commonly used mechanisms for providing force or displacement on a micrometer scale. Devices, such as interdigitated comb-drive actuators, shunt or series switches and capacitive micro-machined ultrasound transducer (CMUT) arrays, rely on electrostatic force to generate actuation at different frequency bands. Micro-machined electrostatic actuators normally need a relatively high voltage bias (typically around 30-50 volts, but sometimes exceeding 100 volts).
A Digital Micromirror Device (DMD) is another micro-machined device using electrostatically actuated mirrors to modulate light. It is used in projectors, high-definition TVs and digital cinemas. Electrostatic forces are generated between the mirror and the underlying complimentary memory electrodes to provide torsional rotation on the mirror hinges causing the mirror to tilt.
DMDs have traditionally been actuated using a bipolar reset waveform between −26 volts and 26 volts. Although memory and digital control electronics have long been integrated underneath the micromirror array, these high-voltage reset waveforms applied on the mirrors have traditionally been provided by a separate power-management and pulse-generation chip, which is packaged in a hybrid configuration and synchronized with the DMD chip through an embedded processor. The synchronization process and packaging parasitics fundamentally limit not only the slew rate, pulse width and separation duration of the reset pulses but also its synchronization with address electrode signals, seriously degrading the mirror dynamics.